Hi. Those figures are very good. As you are approaching the region of 5% to 6% where HBa1C is probably at it's best I would expect any change to come more slowly but it is in the right direction. I would guess you have got the diet right for your blood sugar so keep at it.
It is hard to answer that! whether your diiet is "OK"with regard to HbA1c (and BG in general) depends on many factors, how well your pancreas is producing insulin, how resistant your body is to insulin, whether you are happy at tis level. Many would be happy. others wouldn't.
As you are drifting downward, you could carry on with the current diet, if you are happy with it and see how you proceed as the low 6's isn't terrible :thumbup: